The present invention pertains to the art of microbial decontamination. It finds particular application in conjunction with sterilizing medical equipment and will be described with particular reference thereto. It will be appreciated, however, that the invention is also applicable to disinfecting systems as well as to microbially decontaminating a wide range of items, including dental instruments, endoscopes, laboratory equipment, manufacturing equipment, and other equipment and items on which it is desirable to eliminate microbial life forms.
Sterilization connotes the absence of all life forms, including bacterial endospores which are the living organisms most resistant to conventional sterilants. Disinfection, by distinction, only connotes the absence of pathogenic life forms. Microbial decontamination is generic to both sterilization and disinfection.
Most medical equipment is sterilized at high temperatures. Commonly, the equipment is sterilized in a steam autoclave under a combination of high temperature and pressure. Endoscopes, rubber and plastic devices or portions of devices, such as lenses, and the like may be destroyed or have their useful lives severely curtailed by this heat and pressure.
The more sensitive medical equipment is often sterilized with ethylene oxide, which is thermally less severe than steam. The items must be exposed to the ethylene oxide for a relatively long time, on the order of three and a half hours. Thereafter, eight to twelve hours are normally required for de-gassing or desorbing the ethylene oxide from plastic and other materials which are capable of absorbing the ethylene oxide. The pressurization and depressurization cycles of ethylene oxide sterilization may damage lens systems and other delicate instruments. Moreover, the ethylene oxide is relatively expensive. It is sufficiently toxic and volatile that extensive precautions are commonly taken to assure operator safety.
Liquid systems are commonly used for disinfection of heat sensitive or other delicate instruments. Using liquid sterilants to achieve disinfection is normally rapid, cost effective, and does minimal damage to medical devices. Commonly, a technician mixes a sterilant composition and manually immerses the item to be sterilized. The immersion is timed manually by the technician. Technician variation, liquid sterilant shelf life, and the like raise problems with assurance and reproducibility of the disinfection. Rinsing of the items to remove chemical residues also adds a variable that reduces the assurance of disinfection or sterility. Once the sterilant solution is rinsed, the item is susceptible to reinfection by air borne microbes.
In accordance with the present invention, a new and improved sterilization apparatus, system, and method are provided which overcomes the above referenced problems and others.